Habitability of Exoplanet Waterworlds

We model the evolution of ocean temperature and chemistry for rocky exoplanets with 10-1000 times Earth's H2O but without H2, taking into account C partitioning, high-pressure ice phases, and atmosphere-lithosphere exchange.

We also find, using an ensemble of N-body simulations that include volatile loss during giant impacts, that a substantial fraction of habitable-zone rocky planets emerge after the giant impact era with deep, ice-free water envelopes. This outcome is sensitive to our assumptions of low initial abundances of $^{26}$Al and $^{60}$Fe in protoplanetary disks, plus H$_2$-free accretion. We use the output of the N-body simulations as input to our waterworld evolution code. Thus, for the first time in an an end-to-end calculation, we show that chance variation of initial conditions, with no need for geochemical cycling, can yield multi-Gyr habitability on waterworlds.

We model the evolution of ocean temperature and chemistry for rocky exoplanets with 10-1000 times Earth's H2O but without H2, taking into account C partitioning, high-pressure ice phases, and atmosphere-lithosphere exchange. \n